Adjunctive recombinant human parathyroid hormone agents for the treatment of medication-related osteonecrosis of the jaw: a report of three cases.

Teriparatide has been effective in treating people diagnosed with medication-related osteonecrosis of the jaw (MRONJ). However, its efficacy is not well established to be accepted as a standard of care. The objective of this paper was to investigate the efficacy of recombinant human parathyroid hormone for the treatment of MRONJ. We report three cases of MRONJ patients with osteoporosis as the primary disease who were treated with a teriparatide agent along with other adjunctive measures. Each patient was administered a teriparatide injection subcutaneously for 16 weeks, 36 weeks, or 60 weeks. Surgical intervention including partial resection, sequestrectomy, decortication, and saucerization took place during the teriparatide administration. Complete lesion resolution was identified clinically and radiographically in all three patients. In patients diagnosed with MRONJ, teriparatide therapy is an efficacious and safe therapeutic option to improve healing of bone lesions. These findings demonstrate that teriparatide in combination with another therapy, especially bone morphogenetic protein, platelet-rich fibrin, or antibiotic therapy, can be an effective protocol for MRONJ.

Prediction of medication-related osteonecrosis of the jaws using machine learning methods from estrogen receptor 1 polymorphisms and clinical information.

Objective: The purpose of this study was to evaluate the effect of estrogen receptor 1 (ESR1) polymorphisms on the development of medication-related osteonecrosis of the jaws (MRONJ) in women with osteoporosis. Methods: A total of 125 patients taking bisphosphonates was evaluated the relationship between MRONJ occurrence and single nucleotide polymorphisms (SNPs) of ESR1. Clinical information was collected, including current age, treatment duration, and comorbidity. Univariate and Multivariable regression analyzes were performed to evaluate the independent predictive factors for MRONJ occurrence. Predictive models were constructed using machine learning methods such as Lasso regression, Random forest (RF), and Support vector machine (SVM). The area under the receiver-operating curve (AUROC) was used to evaluate the performance of a binary classifier. Result: Two SNPs of ESR1 (rs4870056 and rs78177662) were significantly associated with MRONJ development. Patients with variant allele (A) of rs4870056 showed 2.45 times (95% CI, 1.03-5.87) the odds of MRONJ occurrence compared to those with wild-type homozygote (GG) after adjusting covariates. Additionally, carriers with variant allele (T) of rs78177662 had higher odds than those with wild-type homozygote (CC) (adjusted odds ratio (aOR), 2.64, 95% CI, 1.00-6.94). Among demographic variables, age ≥ 72 years (aOR, 3.98, 95% CI, 1.60-9.87) and bisphosphonate exposure ≥48 months (aOR, 3.16, 95% CI, 1.26-7.93) were also significant risk factors for MRONJ occurrence. AUROC values of machine learning methods ranged between 0.756-0.806 in the study. Conclusion: Our study showed that the MRONJ occurrence was associated with ESR1 polymorphisms in osteoporotic women.

Narrow Alveolar Ridge Management with Modified Ridge Splitting Technique: A Report of 3 Cases.

Purpose: In this study, we report the usefulness of implant placement with modified ridge splitting technique from three cases of patients with narrow alveolar ridge. Materials and Methods: Three patients were those who visited the Department of Oral and Maxillofacial Surgery of Ewha Medical Center for consultation regarding implant placement. Through clinical and radiographic evaluation, narrowed alveolar ridge after tooth loss was confirmed in all three patients. For them, it was necessary to use the modified ridge split technique with bone augmentation for the implant to be well placed with enough bone width. Results: In all cases, sufficient bone width was confirmed for implant placement, and bone volume was well maintained after prosthetic restoration without any complications. Initial width of alveolar bone was 4.9 mm on average and was well maintained at an average of 7.6 mm at 1-year follow-up after implant installation. Conclusion: Although the number of subjects in this case report was small and was done by only one surgeon, we suggest that modified ridge splitting technique might be a useful surgical method to enhance narrow edentulous alveolar ridges and enable successful implant placement with shorter healing period compared with single guided bone regeneration.

Six-month stability following extensive alveolar bone augmentation by sausage technique.

BACKGROUND: Resorption of alveolar bone is a common sequela of tooth loss and presents a clinical problem, especially in the esthetic zone. When ridge resorption occurs, adequate bone augmentation is essential to obtain satisfactory esthetic results. The purpose of this study was to determine the increase and retention rate of bone height or width in patients who received extensive bone augmentation and to analyze factors affecting its prognosis and stability. METHODS: This study was performed on patients who received extensive bone augmentation by sausage technique at the Department of Oral and Maxillofacial Surgery at Ewha Womans University Mok-dong Hospital from January 1, 2018, to February 28, 2022. CBCT images were taken before and 6 months after surgery to compare the amount of increase in bone height or width at the graft site. They were measured using reliable points such as adjacent implants or cephalometric landmarks, inferior alveolar nerve canals as reference points. RESULTS: A total of 8 patients underwent extensive bone grafting during the given period (mean age was 53.75 years, 2 males and 6 females). Four patients received horizontal augmentation, and 4 received vertical augmentation. When divided by surgical site, 4 patients are in maxilla and 4 in mandible. The average amount of increase in bone width or bone height was 5.38 mm, and the retention rate was about 79.9% after 6 months. The retention rate of horizontal augmentation was 88.8%, which was higher than that of vertical augmentation, which was 74.5%. The maxillary area accounted for 92.2%, and the amount of bone resorption was lower than that of the mandibular area, which was 72.6%. The average stitch out period was about 2.4 weeks, and postoperative dehiscence was observed about 37.5% of the total, more frequently in the mandible (50.0%) than in the maxilla (25.0%). CONCLUSION: In conclusion, extensive bone augmentation achieved significant horizontal or vertical bone height or width increase, and the retention rate after 6 months was also high. In addition, surgery in the maxillary region showed a more successful bone augmentation than in the mandible, with a higher maintenance rate and fewer cases of dehiscence.

Data-driven prediction models for forecasting multistep ahead profiles of mammalian cell culture toward bioprocess digital twins.

Recently, the advancement in process analytical technology and artificial intelligence (AI) has enabled the generation of enormous culture data sets from biomanufacturing processes that produce various recombinant therapeutic proteins (RTPs), such as monoclonal antibodies (mAbs). Thus, now it is very important to exploit them for the enhanced reliability, efficiency, and consistency of the RTP-producing culture processes and for the reduced incipient or abrupt faults. It is achievable by AI-based data-driven models (DDMs), which allow us to correlate biological and process conditions and cell culture states. In this work, we provide practical guidelines for choosing the best combination of model elements to design and implement successful DDMs for given hypothetical in-line data sets during mAb-producing Chinese hamster ovary cell culture, as such enabling us to forecast dynamic behaviors of culture performance such as viable cell density, mAb titer as well as glucose, lactate and ammonia concentrations. To do so, we created DDMs that balance computational load with model accuracy and reliability by identifying the best combination of multistep ahead forecasting strategies, input features, and AI algorithms, which is potentially applicable to implementation of interactive DDM within bioprocess digital twins. We believe this systematic study can help bioprocess engineers start developing predictive DDMs with their own data sets and learn how their cell cultures behave in near future, thereby rendering proactive decision possible.

Explainable deep learning-based clinical decision support engine for MRI-based automated diagnosis of temporomandibular joint anterior disk displacement.

BACKGROUND AND OBJECTIVE: MRI is considered the gold standard for diagnosing anterior disc displacement (ADD), the most common temporomandibular joint (TMJ) disorder. However, even highly trained clinicians find it difficult to integrate the dynamic nature of MRI with the complicated anatomical features of the TMJ. As the first validated study for MRI-based automatic TMJ ADD diagnosis, we propose a clinical decision support engine that diagnoses TMJ ADD using MR images and provides heat maps as the visualized rationale of diagnostic predictions using explainable artificial intelligence. METHODS: The engine builds on two deep learning models. The first deep learning model detects a region of interest (ROI) containing three TMJ components (i.e., temporal bone, disc, and condyle) in the entire sagittal MR image. The second deep learning model classifies TMJ ADD into three classes (i.e., normal, ADD without reduction, and ADD with reduction) within the detected ROI. In this retrospective study, the models were developed and tested on the dataset acquired between April 2005 to April 2020. The additional independent dataset acquired at a different hospital between January 2016 to February 2019 was used for the external test of the classification model. Detection performance was assessed by mean average precision (mAP). Classification performance was assessed by the area under the receiver operating characteristic (AUROC), sensitivity, specificity, and Youden's index. 95% confidence intervals were calculated via non-parametric bootstrap to assess the statistical significance of model performances. RESULTS: The ROI detection model achieved mAP of 0.819 at 0.75 intersection over union (IoU) thresholds in the internal test. In internal and external tests, the ADD classification model achieved AUROC values of 0.985 and 0.960, sensitivities of 0.950 and 0.926, and specificities of 0.919 and 0.892, respectively. CONCLUSIONS: The proposed explainable deep learning-based engine provides clinicians with the predictive result and its visualized rationale. The clinicians can make the final diagnosis by integrating primary diagnostic prediction obtained from the proposed engine with the patient's clinical examination findings.

Recovery from chronic periodontal disease is associated with lower risk for incident diabetes.

AIM: The presence of periodontal disease (PD) at a single time point has been suggested as a predictor of diabetes risk, but whether changes in PD status are associated with altered risk of diabetes is yet to be reported on a population scale. This study investigated whether recovery from or development of PD in a population is associated with an altered risk of diabetes occurrence. MATERIALS AND METHODS: Data of subjects who received health screening from 2002 to 2007 were obtained from the National Health Insurance Service-National Health Screening cohort database of Korea. Patients with a history of diabetes were excluded. Changes in PD status were determined from the first two health screenings. Study subjects were divided into four groups according to the changes in PD status: PD-free, PD-recovered, PD-developed, and PD-chronic. The outcome was the occurrence of diabetes. RESULTS: Overall, 111,611 subjects were included for analysis. During a median follow-up of 9.10 years, diabetes developed in 6102 subjects. The adjusted hazard ratios (HRs) for incident diabetes across various PD change groups (in reference to the PD-free group) were as follows: PD-chronic group = 1.096 (95% confidence interval [CI] 1.026-1.170, p = .006); PD-developed group = 1.073 (95% CI 0.993-1.159, p = .075); and PD-recovered group = 1.019 (95% CI 0.945-1.100, p = .622). The subjects who recovered from PD had a lower diabetes risk than those who had consistent PD (adjusted HR 0.930, 95% CI 0.865-1.000, p = .050), whereas those who developed PD had a higher risk of diabetes than those who remained PD-free. CONCLUSION: The longitudinal change in PD status is associated with incident diabetes risk. Future intervention studies are necessary to determine whether PD treatment can prevent incident diabetes.

Serum biomarkers for bisphosphonate-related osteonecrosis of the jaw: a prospective clinical study.

In this prospective study, serum levels of 12 possible biomarkers were compared between osteonecrosis of the jaw (ONJ) and control groups, before and after dentoalveolar surgery. The results suggest that patients with abnormal serum levels of specific biomarkers should be monitored closely for the prevention and early diagnosis of ONJ. INTRODUCTION: Bisphosphonate-related osteonecrosis of the jaw (ONJ) is an adverse effect of long-term bisphosphonate therapy. This study aimed to identify bone biomarkers for ONJ risk assessment and diagnosis. METHODS: This prospective study included patients with histories of bisphosphonate therapy without current ONJ who were in need of dentoalveolar surgery of the jaw area. Serum levels of 12 possible bone markers, selected based on their involvement in ONJ pathogenesis, were compared between ONJ and control groups before dentoalveolar surgery (T0), at 8 postoperative weeks (T1), and at 4 months after diagnosis(T2). RESULTS: Seventy-six patients who met the inclusion criteria were included in the study; 33 were assigned to the ONJ group, and 43 patients without ONJ signs or symptoms after dentoalveolar surgery were assigned to the control group. In the ONJ group, at both T0 and T1, the mean tartrate-resistant acid phosphatase isoform 5b (TRACP 5b) levels were significantly lower and the mean Dickkopf-related protein 1 (DKK1) levels were significantly higher than the corresponding values for the control group. Linear mixed model analysis revealed significant group effects over time for serum TRACP 5b and DKK1 after adjusting for demographic, pharmacological, and diagnostic variables. Lower serum levels of TRACP 5b under a specified cut-off value (≤ 2.899 U/L) at T0 indicated a 20.40-fold increased risk of ONJ development. CONCLUSION: Patients with abnormally low serum levels of TRACP 5b and high serum levels of DKK1 should be monitored closely before and after dentoalveolar surgery for the prevention and early diagnosis of ONJ.

Can ultrasonography be used to assess capsular distention in the painful temporomandibular joint?

BACKGROUND: To determine whether capsular distention in the painful temporomandibular joint (TMJ) can be assessed by ultrasonography, we compared the capsular width between painful TMJs and painless TMJ. The risk factors for TMJ pain were also investigated including capsular width and other clinical factors such as TMJ sounds that may affect the occurrence and persistence of TMJ pain. METHODS: TMJ ultrasonography was performed on 87 temporomandibular disorder (TMD) patients, including 47 unilateral and 29 bilateral TMJ pain patients, and 11 patients without TMJ pain. RESULTS: The capsular width was greater in the 105 painful joints than in the 69 painless joints. Considering individual anatomical variations, the differences between painful and painless joints in unilateral TMJ pain patients were also analyzed, revealing a greater width in painful joints. Capsular width was a risk factor for TMJ pain with an adjusted odds ratio of 1.496 (95% confidence interval 1.312-1.706; p < 0.001) and was significantly correlated with pain scores. CONCLUSION: This correlation may suggest that pain intensity is associated with widened capsular width because of joint effusion or synovitis. Further studies are required to refine and establish the protocols for standard examinations using ultrasound imaging.

Machine Learning Approaches for Predicting Bisphosphonate-Related Osteonecrosis in Women with Osteoporosis Using VEGFA Gene Polymorphisms.

OBJECTIVE: This nested case-control study aimed to investigate the effects of VEGFA polymorphisms on the development of bisphosphonate-related osteonecrosis of the jaw (BRONJ) in women with osteoporosis. METHODS: Eleven single nucleotide polymorphisms (SNPs) of the VEGFA were assessed in a total of 125 patients. Logistic regression was performed for multivariable analysis. Machine learning algorithms, namely, fivefold cross-validated multivariate logistic regression, elastic net, random forest, and support vector machine, were developed to predict risk factors for BRONJ occurrence. Area under the receiver-operating curve (AUROC) analysis was conducted to assess clinical performance. RESULTS: The VEGFA rs881858 was significantly associated with BRONJ development. The odds of BRONJ development were 6.45 times (95% CI, 1.69-24.65) higher among carriers of the wild-type rs881858 allele compared with variant homozygote carriers after adjusting for covariates. Additionally, variant homozygote (GG) carriers of rs10434 had higher odds than those with wild-type allele (OR, 3.16). Age ≥ 65 years (OR, 16.05) and bisphosphonate exposure ≥ 36 months (OR, 3.67) were also significant risk factors for BRONJ occurrence. AUROC values were higher than 0.78 for all machine learning methods employed in this study. CONCLUSION: Our study showed that the BRONJ occurrence was associated with VEGFA polymorphisms in osteoporotic women.

Medication-related osteonecrosis of the maxilla: Prognosis of oral surgery combined with endoscopic sinus surgery.

OBJECTIVES: To evaluate the effect of functional endoscopic sinus surgery (FESS) on the resolution of maxillary medication-related osteonecrosis of the jaw (MRONJ). PATIENTS AND METHODS: This study included 62 patients diagnosed with MRONJ in the maxillary posterior area with or without maxillary sinusitis (MS). All patients underwent oral surgery. The concomitant MS was evaluated, and if indicated, FESS was performed on the same operation. Follow-up included clinical and radiological examinations at 4 months postoperation. RESULTS: Of the 62 patients, 24 (38.7%) showed no evidence of MS and 38 (61.3%) showed MS. Advanced MRONJ (stage 3), which has bony destruction of the sinus floor and signs of MS according to its definition, was seen in 27 patients (43.5%). In stage 3 MRONJ, patients with combined treatment of oral surgery and FESS compared to those treated with oral surgery alone showed higher percentage of resolution (84.2%, 37.5%, respectively) at 4 months postoperatively, and the results were statistically significant. CONCLUSION: Simultaneous management of MRONJ and sinusitis with combined treatment of oral surgery and FESS for the treatment of maxillary MRONJ can be an effective method, especially for advanced cases, to address its associated lesions.

Tissue Expansion Improves the Outcome and Predictability for Alveolar Bone Augmentation: Prospective, Multicenter, Randomized Controlled Trial.

OBJECTIVES: The purpose of this study was to evaluate the effectiveness of the intraoral use of subperiosteally placed self-inflating tissue expanders for subsequent bone augmentation and implant integrity. MATERIAL AND METHODS: A prospective, multicenter, randomized controlled trial was performed on patients requiring alveolar bone graft for dental implant insertion. Patients were assigned to three groups: tissue expansion and tunneling graft (TET group), tissue expansion and conventional bone graft (TEG), and control group without tissue expansion. Dimensional changes of soft tissue and radiographic vertical bone gain, retention, and peri-implant marginal bone changes were evaluated and secondary outcomes; clinical complications and thickness changes of expanded overlying tissue were assessed. RESULTS: Among 75 patients screened, a total of 57 patients were included in the final analysis. Most patients showed uneventful soft tissue expansion without any inflammatory sign or symptoms. Ultrasonographic measurements of overlying gingiva revealed no thinning after tissue expansion (p > 0.05). Mean soft vertical and horizontal tissue measurements at the end of its expansion were 5.62 and 6.03 mm, respectively. Significantly higher vertical bone gain was shown in the TEG (5.71 ± 1.99 mm) compared with that in the control patients (4.32 ± 0.97 mm; p < 0.05). Hard tissue retention- measured by bone resorption after 6 months-showed that control group showed higher amount of vertical (2.06 ± 1.00 mm) and horizontal bone resorption (1.69 ± 0.81 mm) compared to that of the TEG group (p < 0.05). CONCLUSION: The self-inflating tissue expander effectively augmented soft tissue volume and both conventional bone graft and tunneling techniques confirmed their effectiveness in bone augmentation. With greater amount of bone gain and better 6 month hard tissue integrity, the TEG group compared to the control group-without tissue expansion-showed that the combined modality of tissue expander use and guided bone regeneration (GBR) technique may improve the outcome and predictability of hard tissue augmentation.

Soft tissue expander for vertically atrophied alveolar ridges: Prospective, multicenter, randomized controlled trial.

OBJECTIVES: Conventional guided bone regeneration (GBR) limits the amount of bone graft due to limited soft tissue expansion. We hypothesize that the use of tissue expander will successfully augment soft tissue prior to bone graft, allowing for sufficient amount of grafting which will lead to a more stable and effective vertical bone graft. The authors aimed to evaluate effectiveness of the novel self-inflating tissue expander for vertical augmentation in terms of soft tissue expansion, clinical outcomes, and related complications. MATERIAL AND METHODS: A prospective, multicenter, randomized controlled trial was performed on patients requiring vertical augmentation. For experimental group patients, the tissue expander was subperiosteally implanted and followed by a tunneling bone graft without full flap reflection. Control patients underwent conventional vertical GBR. Primary objectives were to evaluate the dimensional changes of soft tissue and radiographic vertical bone gain and retention. As a secondary outcome, clinical complications and thickness changes of expanded overlying tissue were assessed and analyzed. RESULTS: Twenty-three patients in each group were included. During a 4-week expansion, two of the experimental group showed over-expansion and one showed mucosal perforation associated with previous severe scars. The other patients showed uneventful expansion and mean tissue augmentation was 6.88 ± 1.64 mm vertically. Ultrasonographic measurements of overlying gingiva revealed no thinning after tissue expansion (p > .05). Significantly higher vertical bone gain was shown in the experimental group (5.12 ± 1.25 mm) compared with that in the control patients (4.22 ± 1.15 mm; p < .05). After a 6-month retention period, the mean vertical bone measurement of the controls had decreased to 1.90 mm (55.0% reduction), which was a significantly greater decrease than that in the experimental group (mean 3.55 mm, 30.7% reduction; p < .05). CONCLUSION: Our results demonstrated the effectiveness of tissue expanders followed by tunneling bone graft for vertical augmentation; however, studies comparing the two techniques without tissue expanders are needed to elucidate the net effect of tissue expansion.

Randomized controlled trial on the effectiveness of absorbable collagen sponge after extraction of impacted mandibular third molar: split-mouth design.

BACKGROUND: The purpose of this study was to compare the effectiveness of absorbable collagen sponge insertion in tooth extraction sites for socket healing of the impacted mandibular third molar. METHODS: Thirty-six patients with bilateral mandibular impacted third molars based on Pell-Gregory and Winter classification were included in this study. This study was a randomized clinical trial utilizing a split-mouth design with one side assigned as collagen sponge insertion and the other side assigned as the control. Post-operative clinical complications, periodontal integrities, and radiographic outcomes were assessed at 1, 2, and 14-weeks post operatively. RESULTS: Five patients were excluded during the follow-up period due to loss of follow-up. The study was conducted on 31 patients in total. The mean VAS score of collagen sponge insertion side at 1 week post operation was 1.42 ± 1.26, which was significantly lower than the control side (P < 0.05). The mean probing depth of collagen sponge insertion side at 2-week post operation was 5.55 ± 2.28 mm, which was significantly lower than the control side (7.13 ± 1.86; P < 0.05). Other various measurements including radiographic outcomes showed no significant group differences. CONCLUSIONS: Placement of collagen sponge after extraction of mandibular impacted third molar reduced early stage post-operative complications and enhanced initial healing of soft tissues and periodontal defects. TRIAL REGISTRATION: This study was retrospectively registered at the WHO ICTRP platform and Clinical Research Information Service, KCT0003363. Registered 21 Sep 2018.

Pharmacoepidemiology and clinical characteristics of medication-related osteonecrosis of the jaw.

BACKGROUND: The aim of this study was to investigate clinical and pharmacoepidemiologic characteristics of medication-related osteonecrosis of the jaw. METHODS: The study population is comprised of 86patients who were diagnosed with ONJ at Ewha Womans University Mokdong Hospital from 2008 to 2015. Factors for epidemiologic evaluation were gender, age, location of lesion, and clinical history. The types of bisphosphonates, duration of intake, and the amount of accumulated dose were evaluated for therapeutic response. Clinical symptoms and radiographic images were utilized for the assessment of prognosis. RESULTS: Among the 86 patients, five were male, whereas 81 were female with mean age of 73.98 (range 45-97). Location of the lesion was in the mandible for 58 patients and maxilla in 25 patients. Three patients had both mandible and maxilla affected. This shows that the mandible is more prone to the formation of ONJ lesions compared to the maxilla. ONJ occurred in 38 cases after extraction, nine cases after implant surgery, six cases were denture use, and spontaneously in 33 cases. Seventy-six patients were taking other drugs aside from drugs indicated for osteoporosis. Most of these patients were diagnosed as osteoporosis, rheumatic arthritis, multiple myeloma, or had a history of cancer therapy. Higher weighted total accumulation doses were significantly associated with poorer prognosis (P < 0.05). CONCLUSION: Dose, duration, route, and relative potency of bisphosphonates are significantly associated with treatment prognosis of osteonecrosis of the jaw.

Impaired osseointegration of dental implants associated with orthognathic surgery: Possible regional acceleratory phenomenon.

BACKGROUND: Regional acceleratory phenomenon (RAP) is demonstrated to decrease regional bone mineral density and accelerate bone turnover. Hypothesizing that RAP can negatively affect the osseointegration of biomaterials, this study aimed to investigate the possible influence of the RAP on dental implant osseointegration. MATERIALS AND METHODS: Orthognathic surgery, one of the major surgeries on oral and maxillofacial region was set as intervention for RAP. Considering that RAP exerts its physiologic effects until 4 months after noxious stimuli, patients were classified according to the time interval between orthognathic surgery and dental implant installation; group I was designated to patients who had implant installation within 4 months from orthognathic surgery. Group II were those with installation after 4-12 months and group III was longer than 12 months. Radiographic and clinical evaluations of dental implants including peri-implant marginal bone changes (MBR), implant stability, cumulative survival rates were analyzed. RESULTS: A total of 54 patients with 106 implants (mean follow-up of 72.6 months) were included in the study. MBR was significantly higher in group I (2.62 ± 0.91 mm) and II (2.25 ± 0.95 mm) compared to that of group III (0.94 ± 0.90 mm) at last follow up (P < 0.05) and this group difference over time was also significant (P < 0.001). Compared to group III, groups I and II exhibited lower ISQ values and higher biological complications including peri-implantitis and peri-implant gingivitis (P < 0.05). Group I showed significantly low-cumulative survival rate (89.2%; implant-level) compared to groups II and III. CONCLUSIONS: In this study, impaired osseointegration of dental implants was demonstrated associated with orthognathic surgery. Micro-environmental changes of hard tissue induced by major surgery on the jaw showed deteriorating effects on integrity of biomaterial osseointegration. Special considerations should be addressed for ideal treatment results and prognosis.

Effects of pH alteration on the pathogenesis of medication-related osteonecrosis of the jaw.

INTRODUCTION: An acidic environment has been recognized to increase catabolic activities and inhibit osteoblastic deposition, and also exhibited in the pathogenesis of various bone diseases. The aim of the study was to investigate the role of systemic and local pH alteration in the pathogenesis of medication-related osteonecrosis of the jaw (MRONJ). MATERIAL AND METHODS: Initially, MRONJ was induced in 54 Sprague-Dawley rats via subcutaneous bisphosphonate injections, once a week for 8 weeks. A week prior to bisphosphonate termination, surgical intervention was performed and rats were divided into 3 groups-alkalotic, acidic and control group, wherein each received NaHCO3, NH4Cl and normal saline, respectively for 8 weeks. Upon sacrifice, blood was sent for arterial blood pH analysis and their mandibles were subjected to histomorphometric and µCT analyses. ONJ was histologically defined as necrotic bone persisting for eight weeks after surgical intervention. RESULTS: Each intervention exemplified its expected outcome wherein each group exhibited a borderline alkalotic (7.43 ±â€¯0.05) and acidic state (7.27 ±â€¯37), respectively (P < 0.05). Acidic group showed a higher occurrence of MRONJ (95%) compared to that of alkalotic group (60%) and control (76.9%). Histomorphometric and microstructural evaluation revealed that acidic group presented deteriorated bone architectures with significantly higher necrotic bone fraction, clusters of empty lacunae, N.Oc/B.Pm and lower B.Ar./T.Ar, BV/TV, Tb.Th (P < 0.05). Alkalotic group showed possible protective effects against ONJ versus acidic group, however these trends were not statistically significant. CONCLUSIONS: An acidic milieu aggravated ONJ development in an animal model. Further investigations are needed to elucidate the exact role of acid-base balance in MRONJ pathogenesis and possible benefits of alkali supplementation for the prevention.

From the maxillary sinus to the stomach: a rare case report of a displaced fragment of dental implant.

PURPOSE: To present a rare clinical case of migration of a displaced implant fragment from the maxillary sinus to the stomach. MATERIALS AND METHODS: A 66-year-old man was referred from a local dental clinic to remove a displaced implant apical fragment in the left maxillary sinus. After 15 days from the displacement, no foreign body was seen in the maxillary sinus or in any other craniofacial cavity. Thoracic and abdominal radiographs were taken, and a 3 × 3 mm radiopaque object, which corresponded to the piece of implant fragment, was detected within the patient's stomach. RESULTS: Follow-up radiographs were taken to monitor the progress after 1 week, and it was found that the radiopaque object had disappeared. CONCLUSIONS: A displaced dental implant fragment in the maxillary sinus can migrate and exit from the maxillary sinus within a few days. Since it presents a potential risk for swallowing or aspiration, displaced implants or other objects in the maxillary sinus should be removed immediately. Before removal, additional radiographs are recommended to confirm the current position of the implant.

A case of dystrophic calcification in the masseter muscle.

BACKGROUND: Dystrophic calcification can occur in any soft tissue with the absence of a systemic mineral imbalance and is often associated with trauma, infection, or inflammation. It is easily found in the site of the heart and skeletal muscles and rarely appears in the head and neck area. CASE REPORT: We present a rare case of multiple calcified masses in the left masseter muscle of a 26-year-old female with a history of trauma in the area. In computed tomography, multiple radiopaque masses were observed inside the left masseter muscle and blood test results were normal. The calcified masses were diagnosed as dystrophic calcification and removed by surgery without any complications. CONCLUSION: Different types of calcifications may occur in the cheek area, and they need to be distinguished from dystrophic calcification. Thorough clinical examination and history taking is required together with blood testing and radiographic examinations.

Traumatic Buccal Fat Pad Herniation in Young Children: A Systematic Review and Case Report.

PURPOSE: Traumatic herniation of a buccal fat pad, predominantly seen in young children, is a rare condition. Because of its rarity and clinical features that resemble tumors, clinicians are faced with challenges at the initial diagnosis. This report describes a case of buccal fat pad herniation with excellent long-term prognosis after surgical relocation and conservative treatment and presents a systematic review of the literature on its management. MATERIALS AND METHODS: Through a PubMed search, 811 articles were initially identified. Case series, case reports, technical notes, case and review reports, and retrospective case series were included. After screening and manual review, the sample was narrowed to 35 reports (41 patients) based on eligibility criteria. Articles were included if the standard criteria for traumatic intraoral herniation of buccal fat pad were met. RESULTS: Patients' ages ranged from 4 months to 12 years, with no specific gender predilection. Management consisted of excision (82.9%), relocation (14.6%), and observation (2.4%). Follow-up ranged from 1 week to 4 months. No reports presented a follow-up longer than 4 months; hence, data on long-term prognosis were not reported. For the present case report, a 19-month-old boy diagnosed with traumatic buccal fat pad herniation was successfully treated with surgical relocation and antibiotic support. Twelve-month follow-up showed no esthetic or functional disturbance or recurrence. CONCLUSION: Traumatic herniation of the buccal fat pad requires special attention at the initial diagnosis. Considering its clinical importance in young children and few studies have reported long-term postresection follow-up, surgical relocation can be regarded as an excellent and more conservative treatment option.